Rapid discovery of closest base station in 5G and 6G networks

ABSTRACT

A new user seeking a base station to join must first implement a grueling series of complex steps, which may be especially challenging for the majority of devices expected in next-generation 5G and 6G systems. If the user has a real emergency, such as an imminent traffic collision, then the time wasted in locating (“discovering”) a nearby base station and finally logging on may make the difference between life and death. Disclosed herein are procedures for new users to transmit a “hailing” message on an allocated frequency that multiple base stations continuously monitor. The base stations can then reply at a standard amplitude, so that the new user can determine which base station is closer (or provides the best signal reception) according to the received amplitude. In addition, the reply messages can include a characteristic frequency of the replying base station, such as its entry frequency.

PRIORITY CLAIMS AND RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/585,992, entitled “Hailing Procedure for V2R, V2V, and V2X InitialContact in 5G and 6G”, filed Jan. 27, 2022, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 63/210,216, entitled“Low-Complexity Access and Machine-Type Communication in 5G”, filed Jun.14, 2021, and U.S. Provisional Patent Application Ser. No. 63/214,489,entitled “Low-Complexity Access and Machine-Type Communication in 5G”,filed Jun. 24, 2021, and U.S. Provisional Patent Application Ser. No.63/220,669, entitled “Low-Complexity Access and Machine-TypeCommunication in 5G”, filed Jul. 12, 2021, and U.S. Provisional PatentApplication Ser. No. 63/256,042, entitled “Hailing Procedure for V2R,V2V and V2X Initial Contact in 5G”, filed Oct. 15, 2021, all of whichare hereby incorporated by reference in their entireties.

FIELD OF THE INVENTION

The disclosure involves ways to locate and connect to a 5G or 6Gwireless network.

BACKGROUND OF THE INVENTION

Before communicating on a 5G or 6G cell or network, a new user isrequired to perform a multi-step “discovery” process of finding andinitially contacting a base station of the network, then registering,and eventually being authenticated on the network, a process thatinvolves complex computations, significant delays, and manyuncertainties. When a user device finally locates and attempts to makeinitial contact with a base station, that network may not be open to newentrants, or may not provide accommodations or performance or otherservices that the user device requires. Similar problems inhibitcommunications between vehicles as well as other mobile and fixeddevices. What is needed is a way for user devices, especially mobileuser devices, to find and initially contact a local base station andother wireless entities, with less complexity, uncertainty, and delay.

This Background is provided to introduce a brief context for the Summaryand Detailed Description that follow. This Background is not intended tobe an aid in determining the scope of the claimed subject matter nor beviewed as limiting the claimed subject matter to implementations thatsolve any or all of the disadvantages or problems presented above.

SUMMARY OF THE INVENTION

In a first aspect, there is a method for a wireless user device toselect a base station, the method comprising: broadcasting a hailingmessage on a predetermined hailing frequency, the hailing messagecomprising a request for base stations receiving the hailing message totransmit a reply message; receiving one or more reply messages;selecting whichever reply message is received by the wireless userdevice with the highest received amplitude; selecting whichever basestation transmitted the selected reply message; and transmitting, to theselected base station, an introductory message indicating that thewireless user device seeks entry into a cell of the selected basestation.

In another aspect, there is a base station of a wireless network, thebase station containing non-transitory computer-readable mediacontaining instructions that, when executed by a computing environment,cause a method to be performed, the method comprising; determining apredetermined hailing frequency allocated for user devices to transmithailing messages; receiving a broadcast hailing message from aprospective user device on the predetermined hailing frequency, whereinthe broadcast hailing message indicates that a reply message isrequested from base stations that can accept a new user; determiningthat the base station can accept a new user; measuring an amplitude ofthe broadcast hailing message as received by the base station;calculating a delay time inversely related to the amplitude, the delaytime not exceeding a predetermined maximum delay time; and after thedelay time, transmitting, according to a predetermined transmissionpower level, a reply message to the user device on the predeterminedhailing frequency.

In another aspect, there is a wireless network comprising a first basestation in signal communication with a plurality of user devices, thefirst base station configured to: determine a maximum traffic capacityof the first base station; determine a predetermined limit less than 1;determine a hailing frequency allocated for user devices to transmitdiscovery messages to base stations; measure a fraction comprising acurrent traffic level of the first base station divided by the maximumtraffic capacity of the first base station; if the fraction is below thepredetermined limit, receive a hailing message broadcast by aprospective user device; measure a value related to the hailing message;communicate the value and the fraction to a network administrativeentity; and upon receiving, from the network administrative entity, aninstruction to accept the prospective user device, transmit a replymessage to the prospective user device.

This Summary is provided to introduce a selection of concepts in asimplified form. The concepts are further described in the DetailedDescription section. Elements or steps other than those described inthis Summary are possible, and no element or step is necessarilyrequired. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended foruse as an aid in determining the scope of the claimed subject matter.The claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

These and other embodiments are described in further detail withreference to the figures and accompanying detailed description asprovided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a sketch showing an exemplary embodiment of a hailing messagebroadcast to multiple base stations, according to some embodiments.

FIG. 1B is a chart showing an exemplary embodiment of a series ofresponses to a hailing message, according to some embodiments.

FIG. 2A is a sequence chart showing an exemplary embodiment of a processfor user device to make initial contact with a network, according tosome embodiments.

FIG. 2B is a flowchart showing an exemplary embodiment of a process fora user device to make initial contact with a network, according to someembodiments.

FIG. 3A is a sequence chart showing another exemplary embodiment of aprocess for a user device to make initial contact with a network,according to some embodiments.

FIG. 3B is a flowchart showing another exemplary embodiment of a processfor a user device to make initial contact with a network, according tosome embodiments.

FIG. 4A is a sequence chart showing an exemplary embodiment of a processfor a user device to find system information files, according to someembodiments.

FIG. 4B is a flowchart showing an exemplary embodiment of a process fora user device to find system information files, according to someembodiments.

FIG. 5A is a sequence chart showing an exemplary embodiment of a processfor a base station to reply to a user device, according to someembodiments.

FIG. 5B is a flowchart showing an exemplary embodiment of a process fora base station to reply to a user device, according to some embodiments.

FIG. 6A is a schematic sketch showing an exemplary embodiment of ahailing message, according to some embodiments.

FIG. 6B is a schematic sketch showing an exemplary embodiment of ahailing message with pre-synchronization and identification code,according to some embodiments.

FIG. 6C is a schematic sketch showing an exemplary embodiment of ahailing location message, according to some embodiments.

FIG. 7A is a schematic sketch showing an exemplary embodiment of aresponse redirect message, according to some embodiments.

FIG. 7B is a schematic sketch showing an exemplary embodiment of aresponse redirect message to a random access channel, according to someembodiments.

FIG. 7C is a schematic sketch showing an exemplary embodiment of aresponse redirect message with two frequency redirects, according tosome embodiments.

Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION

5G and 6G technologies are intended for eMBB (enhanced Mobile Broadbandcommunications), URLLC (ultra reliable low latency communications), andmMTC (massive machine-type communication) generally involving largenumbers of user devices such as vehicles, mobile phones, self-propelledand robotic machines, portable and stationary computers, and many otheradvanced wireless instruments. A new user that wishes to transmit a datamessage in 5G or 6G is required to perform a complex series of stepsstarting with a “blind search” through a potentially large number offrequencies until finding (“discovering”) a system information messagefrom one of the base stations in range, and then following a multi-stepprocedure of message exchanges and delays before being able to transmitthe data message. A mobile device seeking communication with anotherdevice, such as a vehicle in traffic or a roadside wireless device, mustperform a similar time-consuming and uncertain search.

The overall goal of 5G/6G is to maximize performance, as measured byhigh volume capacity, high speed data flow, low latency, and highlyreliable communications among wireless devices that are assumed to behighly competent. However, many planned wireless IoT (internet ofthings) applications involve low-cost, single-purpose devices withreduced capabilities (RedCap) which may have difficulty completing thisarduous initialization process. Many if not most of the future MTC(machine-type communication) devices are expected to be low-cost,narrow-bandwidth, reduced-capability devices designed for a singlepurpose, such as sensors and actuators. Such devices generally do notrequire high performance communications, have low QoS (quality ofservice) needs, and may have difficulty complying with the complexrequirements of 5G and 6G. An efficient way to accommodate bothhigh-performance users and reduced-capability devices may be to providelow-complexity alternatives and options in a manner that avoidsburdening base stations and avoids interfering with higher-priorityusers. That is the intent of the procedures presented below.

Disclosed herein are low-complexity procedures enabling user devices tofind 5G/6G base stations and other wireless entities, make initialcontact with them, and continue communicating wirelessly. Systems andmethods disclosed herein (the “systems” and “methods”, also occasionallytermed “embodiments” or “arrangements”, generally according to presentprinciples) can provide urgently needed wireless communication protocolsto reduce access complexity and delays, by providing low-complexityoptions to accommodate reduced-capability user devices in networks suchas 5G and 6G networks, according to some embodiments. The disclosedsystems and methods are generally intended to facilitate“initialization” which includes a prospective user device finding asuitable base station, acquiring system information about the basestation's network, making initial contact with the base station,receiving and processing a first response message from the base station,and completing the registration process on that network. Initializationalso includes user devices seeking wireless entities other than basestations, such as vehicles in traffic, other mobile devices, fixedwireless assets, and the like. Embodiments of the systems and methodsmay include a “hailing” message, which is a message broadcast by a userdevice to make initial contact with one or more proximate entities, andresponsive messaging by those base stations or entities. Embodiments mayinclude procedures for V2N (vehicle-to-network) initialization, V2V(vehicle-to-vehicle) initialization, and V2X (vehicle-to-everything)initialization. The user device may broadcast a hailing message toprompt responsive messages from other transmitters within range. Thehailing message may indicate whether the user device seeks communicationwith a base station, a vehicle, or any wireless entity. Additionalembodiments may include a low-complexity channel or allocated frequency,on which reduced-capability user devices may communicate. Otherembodiments may include message formats such as low-complexity hailingmessage formats and their response messages. The prospective userdevice, by broadcasting such a hailing message and receiving one or moreresponse messages from proximate wireless entities, may thereby initiatecommunication with a selected one of the entities by transmitting anintroductory message to the selected entity, while avoiding manyuncertain and time-consuming 5G/6G procedures.

Some embodiments of the systems and methods may include low-complexityprocedures. Such low-complexity procedures may be configured to avoidhigh-speed signal processing and other challenging computational steps,specifically those employed in standard 5G/6G communications such as“scrambling” in which a message or an error-check code is mixed with anidentity code of the intended recipient, requiring all user devices toanalyze all downlink control signals to determine whether a messageaddressed to them is present. Unfortunately, scrambling prevents theintended recipient from recognizing and mitigating interference andmessage faults, because faulted messages to the user device do notappear to be addressed to the user device, as a consequence of thescrambling. Further challenging process steps may include “DFTprecoding” (discrete Fourier transform), “rate-matching”, “bitinterleaving”, “segmenting”, “turbo encoding”, “column permutation”, andother operations that may not be needed for low-complexity IoT tasks,and may excessively burden reduced-capability user devices. Low latencyand ultra-reliable messaging may provide little or no advantage tolow-cost, low-performance devices that transmit and receive only briefand infrequent messages, as is typical of MTC applications. Instead, inexamples below, a message may be modulated directly from the plain-textmessage bits, transmitted sequentially on a particular frequency,demodulated by the receiver, and interpreted by the receiving entitywithout further processing. Application developers will demand ways toaccess networks using bandwidths and protocols appropriate to thesimpler devices. It is important to provide such low-complexity optionsearly in the 6G roll-out, while such flexibility can still beincorporated in the system design.

Terms herein generally follow 3GPP (third generation partnershipproject) standards, but with clarification where needed to resolveambiguities. As used herein, “5G” represents fifth-generation, and “6G”sixth generation, wireless technology. “NB-IoT” (narrow-bandInternet-of-things) and “5G-Light” are versions that provide slightlyreduced complexity and bandwidth requirements. A network (or cell or LANor local area network or the like) may include a base station (or gNB orgeneration-node-B or eNB or evolution-node-B or access point) in signalcommunication with a plurality of user devices (or UE or user equipmentor user nodes or terminals) and operationally connected to a corenetwork (CN) which handles non-radio tasks such as administration, andis usually connected to a larger network such as the Internet. Thetime-frequency space is generally configured as a “resource grid”including a number of “resource elements”, each resource element being aspecific unit of time termed a “symbol period” (or OFDM symbol,orthogonal frequency-division multiplexing) and a specific frequency andbandwidth termed a “subcarrier” (or “subchannel” in some references).The time domain may be divided into ten-millisecond frames,one-millisecond subframes, and some number of slots, each slot including14 symbol periods. The number of slots per subframe ranges from 1 to 8depending on the “numerology” selected. The frequency axis is dividedinto “resource blocks” (also termed “channels” or “resource elementgroups” in references) including 12 subcarriers. Each subcarrier is at aslightly different frequency and can be independently modulated toconvey message information. The “numerology” of a resource gridcorresponds to the subcarrier spacing in the frequency domain.Subcarrier spacings of 15, 30, 60, 120, and 240 kHz are defined invarious numerologies. Thus a resource element, spanning a single symbolperiod in time and a single subcarrier in frequency, is the smallestunit of a message. Communication in 5G/6G generally takes place onabstract message “channels” (not to be confused with frequency channels)representing different types of messages, embodied as a PDCCH and PUCCH(physical downlink and uplink control channels) for transmitting controlinformation, PDSCH and PUSCH (physical downlink and uplink sharedchannels) for transmitting data and other non-control information, PBCH(physical broadcast channel) for transmitting information to multipleuser devices, among other channels that may be in use. In addition, oneor more random access channels, termed “RACH” herein, also called PRACHin references, represents both abstract and physical random accesschannels, including potentially multiple random access channels in asingle cell, and configured for uplink and/or downlink, as detailedbelow. “CRC” (cyclic redundancy code) is an error-checking code. “RNTI”(radio network temporary identity) is a network-assigned user code. An“SSB” (system synchronization block) is a complex message, normally onthe PBCH, providing system information to new users, including how toreceive messages. A “SIB1” (system information block number 1) isanother system information message, normally on the PDSCH, instructingnew users on how to transmit messages to the base station. A “preamble”is a message transmitted by a prospective user device on a random accesschannel requesting entry into a cell. An “RAR” (random access response)is a message sent by a base station responsive to a preamble message,providing a new user with a temporary identification and other data.

In addition to the 3GPP terms, the following are used herein. To avoidconfusion with the term “symbol”, each modulated resource element of amessage is referred to as a “modulated message resource element” or a“message element” in examples below. Each resource element of ademodulation reference is referred to as a “reference element”. Amessage may be configured “time-spanning” by occupying sequential symbolperiods at a single frequency, and “frequency-spanning” on multiplesubcarriers or subchannels at a single symbol period. Those terms areoften conflated with TDD (time-division duplexing) and FDD(frequency-division duplexing), which refer to message duplexing. Amessage is “unicast” if it is addressed to a specific recipient, and“broadcast” if it includes no recipient address. Transmissions are“isotropic” if they provide roughly the same wave energy in allhorizontal directions. A device “knows” something if it has the relevantinformation. A message is “faulted” or “corrupted” if one or more bitsof the message are altered relative to the original message. “Random”and “pseudorandom” may be used interchangeably. References often use thesame term for two different things. For example, “RACH” may refer to arandom access message or to the channel on which it is transmitted or tothe initial log-in procedure, “PBCH” may refer to a system informationmessage or to the time-frequency resources on which it appears.Disambiguation will be provided when necessary.

As used herein, “low-complexity” refers to procedures necessary forwireless communication, exclusive of procedures providinghigh-performance communication. 5G and especially 6G include manyprocedures and requirements greatly exceeding those necessary forwireless communication, but necessary for high volume at low latency andhigh reliability. Compared to scheduled and managed 5G/6G messaging,low-complexity procedures generally require less computation and lesssignal processing. For ease of reception, low-complexity messages aregenerally modulated directly from the initial message, without furtherencoding or other modifications, so that each received message elementcan be demodulated and interpreted according to the original messagedata without additional signal processing or other processing.Low-complexity procedures may be tailored, or defaults may beestablished, to minimize the number of separate operations required of auser device. Low-complexity procedures may provide means for asingle-purpose wireless product to be developed around a simple low-costtransceiver and a simple processor such as a microcontroller or ASIC(application-specific integrated circuit). One intent of thelow-complexity procedures may be that the processor may thereby dedicateits efforts primarily to serving its intended application, rather thancarrying out complex 5G/6G requirements.

“Reduced-capability” refers to wireless devices that cannot comply with5G or 6G protocols, absent the systems and methods disclosed herein. IA“low-complexity channel” refers to a frequency or a band of frequenciesallocated for user device communications meeting certain predeterminedcriteria. The criteria may include a limit on the size of messages, alimit on the number of messages or volume per day, or a limit on thetransmitted power level. Communications on the low-complexity channelmay be transmitted at-will or without grant, according to someembodiments. Transmissions may be narrow-band such as 100 kHz,single-tone or single-frequency, and time-spanning, according to someembodiments. The low-complexity channel may employ a default modulationsuch as QPSK and a default demodulation reference signal, according tosome embodiments. Messages transmitted by user devices may be alignedwith the resource grid and may be managed by base station usingtime-alignment messages in some embodiments, and in other embodimentsthe messages may have no synchronization with the base station'sresource grid. User devices may be expected to monitor the channelduring an LBT (listen-before-talk) interval before transmitting to avoidmessage collisions.

The systems and methods disclosed herein include a “hailing” message,which is a message broadcast by a prospective user device on apredetermined hailing channel at a predetermined hailing frequency,configured to prompt a responsive reply message from one or morereceiving entities such as base stations or vehicles or fixed assets.The hailing message may indicate that it is a hailing message byincluding a code, such as a hailing-message code termed a “type-code”herein. The hailing message or its hailing type-code may implicitlyindicate that any wireless entities that receive the message arerequested to transmit a reply message if they are able to communicatewith new users. The hailing device may then transmit an “introductorymessage” to one of the entities, requesting further communication and/orentry into a cell or LAN. For example, the user device may broadcast ahailing message to find and register on a proximate base station, or tolocalize and communicate with another vehicle, or to make initialcontact with another wireless entity of any type. The hailing messagemay include an indication, termed a “seek-code” herein, indicatingwhether the hailing user device seeks contact with a base station, afellow vehicle, or any receiver without restriction (that is, V2N, V2V,or V2X) according to the seek-code in the hailing message. Thus thehailing message, by indicating that it is a hailing message, therebyimplicitly requests a reply message from base stations or other entitiesthat receive it. Alternatively, a seek-code included in the hailingmessage may explicitly request a reply message from wireless entities ofthe indicated type.

The “introductory message” is a message transmitted by the user deviceto one of the entities that have responded to its hailing message. Theintroductory message provides information about the hailing user deviceand requests further communication. If the responding entity is a basestation, the introductory message may be a random access preambletransmitted on the base station's random access channel, which is arequest to join the base station's cell. Alternatively, if the userdevice wishes to communicate on the hailing channel, the introductorymessage may indicate that the user device is a reduced-capability deviceand/or requests continuing communication on the hailing channel or otherlow-complexity channel. If the responding entity is a vehicle, theintroductory message may be a sidelink message addressed to theresponding vehicle. If the responding entity is another type of wirelesstransmitter, the introductory message may be addressed to the respondingentity and/or may include information about the hailing user device.

In some embodiments, the hailing channel may be a low-complexitychannel, may be separate from the scheduled channels of 5G/6G, and maybe configured to accommodate at-will transmissions fromreduced-capability user devices. Prospective users may then broadcasthailing messages on the hailing channel to make first contact with abase station, for example. In some embodiments, a hailing message mayindicate the location of the hailing node and/or an identification codeand/or other information about the prospective user device or itsrequirements.

In some embodiments, the hailing message and the reply messages may beconfigured to enable the hailing user device to select the closestresponding entity (or the one with the strongest signal) forcommunication. For example, the responding entities may be configured towait a “reply delay” interval before responding to the hailing message,wherein the reply delay is calculated according to the amplitude orstrength of the hailing message, as-received by the responding entity.For example, a responding entity may delay a shorter time if thereceived amplitude of the hailing message is higher than a predeterminedvalue, and a longer time if the received amplitude is lower.Alternatively, the replying entities may include a formula or algorithmconfigured to calculate the reply delay according to the measured signalamplitude or received power level. Such an amplitude-dependent replydelay may thereby provide that the entity with the strongest receivedsignal replies soonest and the entity with the weakest received signalreplies last, or at least much later than the soonest one. The closestresponding entity is then the first to reply since it likely has thehighest received signal. The user device may then communicate with thefirst-replying entity, thereby obtaining the best signal reception. Inmost cases, communication is reciprocal, which means that the userdevice will likely get the best reception from the entity that receivesthe hailing message with the highest amplitude. In some embodiments, thereply messages may include information about each replying entity, suchas its ID code, or a particular frequency on which the hailing userdevice can communicate directly with the replying entity, for example.

In other embodiments, a plurality of entities may receive a hailingmessage, but only one of the entities may reply to the hailing message.The entities may communicate with each other to determine which one willreply. For example, a base station with low traffic density mayvolunteer to reply to the hailing message even if it is not the closestone, whereas another base station that is heavily loaded may decline toreply even if it is the closest one. In some embodiments, an algorithmbased on artificial intelligence or machine learning may be used by thebase stations to determine which base station will reply to the hailingmessage.

In the V2X application, a vehicle may seek communication with anyreceiver in range. Wireless entities proximate to the vehicle mayreceive the vehicle's hailing message and may then reply, after a replydelay based on received signal strength. The V2X hailing message and/orthe reply message may include a code identifying the transmittingentity, such as its MAC (media access control) address, so that thevehicle and other wireless devices may then communicate unicast, as longas they are in range of each other. The V2X reply delay may beconfigured to avoid message collisions. If the reply delay is inverselyrelated to the amplitude of the as-received hailing message, the replymessages will be distributed in time, thereby avoiding most messagecollisions. Alternatively, each reply may be delayed randomly (within apredetermined maximum limit) to avoid message collisions. Such arandomly-selected reply delay may be necessary if a large number ofother vehicles are nearby in closely-spaced traffic, since theamplitude-dependent delay may be insufficient to separate the replies intime. In addition, each replying entity may perform a listen-before-talk(LBT) delay before transmitting.

Turning now to the figures, FIG. 1A is a sketch showing an exemplaryembodiment of a hailing message broadcast by a prospective user tomultiple base stations (or other wireless entities), according to someembodiments. As depicted in this non-limiting example, a user device100, depicted as a vehicle, may transmit a hailing message 109, whichmay be received by nearby entities, depicted as base station antennas101, 102, 103, 104, 105, and 106. The base stations 101-106 may be atdifferent distances from the user device 100, one such distanceindicated by an arrow 108. Due to spreading and attenuation of thesignal, the hailing message 109 may arrive at each base station 101-106with a different amplitude or power density. The base stations 101-106may be configured to measure the received amplitude or power of thehailing message 109 and to transmit a reply after a calculated replydelay. The reply delay may be calculated inversely according to thereceived amplitude or power, such as delaying longer if the receivedamplitude is lower, and delaying less if the received amplitude islarger. The nearest base station, which in this case is 101, may havethe highest received amplitude, and therefore may calculate the shortestdelay, and therefore may be the first to reply. The user device 100 maybe configured to communicate with the first-replying base station orentity. Since electromagnetic propagation is usually similar in bothdirections, the user device is likely to have the best signal receptionfrom whichever entity receives the hailing message with the highestamplitude. In some embodiments, the remaining base stations 102-106 mayreply later, after a reply delay calculated according to their lowerreceived amplitudes. In other embodiments, the remaining base stations102-106 may detect the earlier reply from base station 101, andtherefore may decline to respond at all. (Note that the reply delays arenot due to the signal travel time from the hailing node to eachreceiving entity. The propagation time is negligible. The reply delaysare calculated according to the received signal amplitude, and areimposed intentionally before each reply is transmitted.)

In some embodiments, the user device 100 may determine that more thanone hailing frequency is available at a particular location, such as aboundary between two networking regions, or a region in which vehiclesand fixed assets use different hailing frequencies. For example, a firsthailing frequency may be monitored by a first set of base stations and asecond hailing frequency may be monitored by a second set of basestations (or other entities). The user device may transmit a firsthailing message on the first hailing frequency and receive one or morereply messages from the first set of base stations, and may transmit asecond hailing message on the second hailing frequency and receive oneor more additional reply messages from the second set of base stations.The user device may then select, from the various reply messages,whichever one arrives at the user device with the least delay. The userdevice can thereby communicate with the receiving entity in either setthat provides the best signal.

In some embodiments, the icons marked 101-106 may represent wirelessdevices other than base stations, such as other vehicles, mobile phones,automated toll booths, and innumerable other wireless devices. Likewise,the user device 100 may represent a wireless entity other than avehicle, such as a wireless phone or a portable computer.

In some embodiments, the reply delay may be configured inversely to thereceived amplitude. In other embodiments, the reply delay may bedetermined randomly, or otherwise.

In some embodiments, the user device 100 and replying entities 101-106may communicate on the same hailing channel after the user device 100selects one of them for further communication. In other embodiments, theuser device 100 and the first-replying entity 101 may continuecommunicating on another channel allocated for V2X or X2X messaging.

In some embodiments, the hailing message may include an indication, suchas a code or flag, of the type of entity sought by the user device 100.The other entities 102-106 may then determine whether to reply accordingto their type. For example, the hailing message may indicate that theuser device 100 seeks other vehicles (V2V) or base stations (V2N) or anywireless entity (V2X). In other embodiments, separate hailingfrequencies may be allocated to each type of entity so they cancommunicate without interference. In that case, the user device 100 maytransmit the hailing message on whichever frequency corresponds to thetype of entity being sought.

In some embodiments, a publicly accessible tabulation of hailingfrequencies may be maintained and configured to be available to userdevices. The tabulation may list hailing frequencies according tolocation and, optionally, the type of entity sought. For example, thetabulation may be available on the Internet, or included in a wirelessdevice, or provided on a plug-in card such as a SIM card, among manyother means of providing the tabulation. A user device may thendetermine, from the tabulation, which frequency to use for transmittinghailing messages based on location. In some embodiments, the tabulationmay also indicate other parameters that the user device may need, suchas the communication bandwidths, modulation types, formats, and so forthin use on each hailing frequency. For example, a reduced-capability userdevice may select, according to information in the tabulation, a hailingfrequency that supports low-complexity messaging, whereas a moredemanding user may select a hailing frequency reserved forhigh-performance communications.

FIG. 1B is a chart showing an exemplary embodiment of the hailingmessage as received by various base stations, according to someembodiments. As depicted in this non-limiting example, six basestations, such as those of FIG. 1A, receive a hailing message. Sinewaves 121 depict the amplitude of the hailing message as received byeach of the base stations. Base station 1 has the strongest receivedsignal and base station 6 has the weakest. Each base station thentransmits a reply message after a reply delay. The reply delay iscalculated by each base station to be inversely related to the receivedamplitude, so that the base station with the largest received amplitudecalculates the shortest delay and replies first.

Also shown is a sequence chart with time horizontal, indicating when thebase stations send their reply messages. The reply messages are labeledas 111, 112, 113, 114, 115, and 116, and are positioned relative to thetime of the hailing message which is at time 110. Base station 1 gas thelargest received amplitude and therefore the shortest delay, andtherefore is the first to transmit its reply message 111. The otherreply messages 112-116 are shown dashed because, in this case, each basestation monitors the hailing channel and refrains from transmitting ifthey detect another base station's reply during their delay time. Basestation 1, on the other hand, did not refrain from transmitting becauseit did not detect any other reply message during its delay, andtherefore transmitted its reply 111 first. The other base stationsrefrained from transmitting their replies 112-116 after detecting basestation 1's reply 111. (In another embodiment, described below, all thebase stations transmit their replies regardless of whether they detectanother reply, so that the hailing user device can select which basestation to communicate with.)

In some embodiments, a maximum delay time may be predetermined, suchthat base stations calculating their reply delays are limited to nogreater than the maximum delay time. The maximum delay time, labeled120, may enable the hailing user device to determine when to expect thelast of the responses. Accordingly, base stations 5 and 6 transmit theirreply messages 115-116 at the maximum time 120, although their differentreceived amplitudes would otherwise cause them to calculate different,and longer, delay times. In some embodiments, each base station may beconfigured to add or subtract a small random extra time to the maximumdelay time 120, so that their transmissions are less likely to collide.In a remote or sparsely-covered wireless environment, the nearest basestation to a user device may be quite distant, and therefore may be theonly base station able to reply to the hailing message. In that case,the user device may detect the solo reply message at the maximum timeand may attempt to communicate with that base station. Sincecommunication may be difficult at long range, the user device and thebase station may employ procedures to enhance reliability, such asincreasing the transmission power, reducing the data rate, transmittingmessages twice, and so forth. In addition, if the user device hasreceived no replies within the maximum delay time, then the user devicecan conclude that there is no coverage at this location.

In some embodiments, a second user device may seek entry at about thesame time as a first user device. In that case, the second user devicecan monitor the hailing frequency and detect the first user device'shailing message. The second user device can then wait until the maximumdelay time after the first user device's hailing message, and then maytransmit its own hailing message, knowing that the second hailingmessage is not interfering with any replies to the first hailingmessage. In other embodiments, the second user device may monitor thevarious base station replies and determine, from the amplitude of eachof the reply messages as received by the second user device, how closeeach base station is to the second user device. The second user devicecan then select the base station with the largest as-received amplitudeat the location of the second user device, and can log on to that basestation. Preferably the second user does not select the first-replyingbase station, because the first user device is about to communicate withthat one. However, if the first-replying base station is indeed the onewith the best reception at the second user device, then the second userdevice may wait until the first user device has finished logging on andthen may seek communication with that same base station. Since thesecond user device has already decided which base station to use, thereis no need to transmit another hailing message.

An advantage of allocating a particular frequency for hailing messagesmay be that a user device may locate and communicate with a proximatebase station, and can select the one that provides the best reception.Another advantage may be that the user device may avoid the arduousfrequency search to locate the base station. An advantage of a maximumdelay time may be that the user device, and other waiting user devices,may thereby know when all of the hailing replies are finished.

Another advantage may be that the depicted low-complexity procedures maybe compatible with devices that may have difficulty complying withprior-art registration procedures. Another advantage may be that thedepicted procedures of FIG. 1A or 1B may be implemented as a software(or firmware) update, without requiring new hardware development, andtherefore may be implemented at low cost, according to some embodiments.The procedures of FIG. 1A or 1B may be implemented as a system orapparatus, a method, or instructions in non-transient computer-readablemedia for causing a computing environment, such as a user device, a basestation, or other signally coupled component of a wireless network, toimplement the procedure. The advantages listed in this paragraph aretrue for each of the lists of advantages in examples below. Particularembodiments may include one, some, or none of the above-mentionedadvantages. Other advantages will be apparent to one of ordinary skillin the art, given this teaching. This comment applies additionally toother lists of advantages provided below.

The systems and methods disclosed herein further include proceduresenabling a user device to initiate communication with a suitableproximate base station, as described in the following examples.

FIG. 2A is a sequence chart showing an exemplary embodiment of alow-complexity procedure for discovering and making contact with a basestation or other entity, according to some embodiments. Horizontal linesshow messages of the user device and of three wireless entities such asbase stations. As depicted in this non-limiting example, the messagesare all on a particular hailing channel, which is a frequency orfrequency band allocated for initial contact messages. A prospectiveuser device may broadcast a hailing message on the hailing channel andthen wait for one or more reply messages from a proximate base station(or other entity), on the same hailing channel. The hailing channel maybe monitored by multiple base stations for detecting the hailingmessages and responding to them.

First, the user device transmits a hailing message 200 on the hailingchannel. The hailing message may contain a code or other indication thatthe message 200 is a hailing message from a prospective user device, andmay also include a demodulation reference and/or an identification codeof the user device and/or a location of the user device, and/or flags,and/or a code indicating which type of entity is being sought, and/orother data.

The hailing message 200 then propagates outward, and attenuates as itpropagates due to spreading of the signal, atmospheric absorption,scattering, intervening buildings or hills, and other attenuationcauses. Assuming that the three entities are located at three differentdistances from the user device, or at least that they have differentattenuation factors, the hailing message 200 will be receiveddifferently at each of the receivers. In the figure, three stippled barsare shown, labeled as 204, indicating graphically the signal strengthas-received at each of the three entities. The three stippled bars 204thus indicate, by their height, that entity 1 has the best receivedsignal strength and entity 3 has the worst received signal. Therefore,the user device will probably have the best reception from entity 1.

The entities may be configured to measure their as-received amplitude ofthe hailing message 200, and may then reply after a calculated replydelay, according to some embodiments. The reply message may betransmitted on the same hailing frequency, as depicted, or alternativelyon another frequency allocated for reply messages. The reply delay maybe calculated according to the received signal strength, so that theentity with the best received signal may be the first to reply. Forexample, the reply delay may be longer for a weaker received signal andshorter for a stronger received signal. Theinversely-amplitude-dependent reply delay may thereby cause the entitywith the best reception to answer the hailing message first. The otherentities, having received weaker signals, are still delaying when thefirst entity transmits its reply message. The other entities may detectthe first entity's reply message 211, and therefore they may thendecline to reply, or they may reply anyway, depending on the embodiment.

The entities may be configured to calculate their reply delays in aconsistent manner, according to some embodiments. The entities may beconfigured to measure their received signal amplitudes in the same way.For example, each entity may include a memory with instructions forcalculating a delay value according to an amplitude value, such as adelay inversely related to the amplitude (that is, a longer delay for aweaker signal and a shorter delay for a stronger signal as-received).Each entity may be equipped with the same (or functionally equivalent)calculation instructions, so that their delays are ordered according toa commonly agreed measure of amplitude strength or signal quality.

The receiving entities may calibrate their receivers so that they allcalculate the delay consistently. For example, a mobile transmitter withan isotropic emission may transmit a test message, or a hailing message,from various known locations, and the various receivers may measuretheir received amplitudes at their locations. The entities may thenadjust their receiver gains, or a threshold value, or other equivalentparameter, to calibrate their amplitude values consistently with eachother. The entities may then use the calibrated values for calculatingtheir reply delays in a consistent manner.

The three delays 201, 202, and 203 are shown successively longer,according to the successively smaller received amplitudes 204 of thethree entities. Accordingly, entity 1 has the highest amplitude and theshortest delay. Then, after the entity 1 delay 201, entity 1, havingdetected no other replies during its delay 201, therefore transmits itsreply 211. The reply in this case is an identification message 211indicating the identity or MAC address or the like, of entity 1. Inaddition, (optionally in dash) entity 1 may include a system informationmessage 214, which may assist the user device by providing a frequencyof an entry channel, such as a random access channel or the like. In themean time, entities 2 and 3 detect entity 1's reply 211 and therefore donot respond. Their avoided reply messages (“skip reply”) are showndashed as 212 and 213. In this way, the user device may become connectedwith the closest entity (or the one with the best reception), and mayalso receive system information, without having to perform a blindsearch across a frequency raster, which may be a significant savings intime and complexity.

In some embodiments, the reply message 211 may include a frequencyredirect message. A “redirect” is a short message indicating a differentfrequency. For example, the redirect message may indicate a PBCHfrequency, where the user device may obtain system information whileavoiding the frequency raster search.

In some embodiments, the reply message 211 may be a low-complexitymessage, configured to enable a reduced-capability user device tocommunicate on a low-complexity channel without performing complexprocedures required of high-performance user devices. For example, thereply message 211 may be an entry message including an assignedtemporary identification code, which the user device may then use whencontinuing to communicate at-will on the low-complexity hailing channelor another low-complexity channel allocated for reduced-capabilitydevice communications.

In some embodiments, a base station may detect a user device's hailingmessage, but that base station may be closed (such as proprietary orprivate or classified cell, for example). In that case, the closed basestation may ignore the hailing message, even if it has the bestreception. However, if the hailing message includes an emergency flag,then the base station with the best reception may reply even if closed,since emergency messaging is a higher priority.

Since the hailing channel may be accessible to multiple prospective userdevices, there is a possibility of a collision between hailing messagesif two user devices transmit hailing messages at the same time. Tominimize collisions and other confusion, the user devices may apply anLBT or listen-before-talk interval before transmitting, according tosome embodiments. The LBT interval may be a predetermined interval longenough to detect cross traffic on the hailing channel. If a first userdevice and a second user device both wish to send hailing messages, andthe second user device detects the first user device's hailing messageduring the LBT interval, then the second user device may withhold itshailing message until after the various base stations have finishedreplying to the first user device's hailing message, and only then mayissue its own hailing message. For example, the second user device maywait until the maximum reply delay limit has been reached, and then maytransmit its own hailing message.

In some embodiments, the second user device may measure the amplitude ofthe first user device's hailing message and determine that the seconduser device is probably close to the first user device based on thereceived amplitude. The second user device may then receive the firstreply message, and note the redirect frequency or system informationincluded in that reply message, notwithstanding that the reply messagewas intended for the other user device. The second user device may thenwait until the first user device has completed its communication withthe selected base station, and then may communicate with the same basestation on the provided frequency. Since the first and second userdevices are close, in this example, the same base station may serve themboth.

Since the hailing channel may be shared by numerous base stations orother entitles, there is a possibility of a collision between the replymessages. For example, in case two base stations measure the sameas-received amplitude, they may calculate the same delay, and theirreply messages may collide or interfere. In that case, the user devicemay receive a garbled reply from those two base stations. The collidingbase stations may not be able to determine that the collision hasoccurred if they both start at the same time. In that case, the userdevice may wait a delay corresponding to the maximum reply delay limit,and may then re-transmit its hailing message a second time. The two basestations that had transmitted replies to the first hailing message maythen conclude, upon receiving the second hailing message, that theirfirst replies were not received successfully, presumably due to acollision. To prevent another collision, the two base stations thattransmitted replies to the first hailing message may then reply again tothe second hailing message, but with their delays modified by randomlyselected additional delays. The random additional delays may make asecond collision unlikely. Then, whichever base station happens to replysooner may prevail, and the other one may remain silent.

While the depicted example has been described with reference to vehiclescommunicating with base stations, the principles may be applied as wellto V2X and X2X applications in which the vehicle (or other entity) seekscommunication with any type of receiver including other vehicles, othermobile terminals, and fixed assets. Each aspect described with referenceto vehicle-base station hailing and replies in the examples below may beadapted straightforwardly to the V2X and X2X applications, bysubstituting “wireless device” for “base station” in each instance, aswill be apparent to artisans with ordinary skill after reading thecurrent disclosure.

FIG. 2B is a flowchart showing an exemplary embodiment of a procedurefor finding and contacting a closest base station, according to someembodiments. As depicted in this non-limiting example, at 250, aprospective user device determines a frequency of a hailing channel. Thefrequency may be a standard and universal frequency such as 1000 MHz, orit may be specified according to location, or provided in a networkdatabase, or on-line, or built-in to the user device, or previouslyobtained, or otherwise. At 251, the user device transmits a hailingmessage on the hailing channel. The hailing message is transmitted as abroadcast, intended for all base stations that can receive it. At 252,one or more base stations receive the hailing message and measure thereceived amplitude (or received power or other measure of signalquality) of the message. Each base station then calculates a reply delayusing a formula (or other calculation tool) based on the measured signalamplitude. The formula may be configured to provide longer delays forlower signal amplitudes, and shorter delays for higher signalamplitudes. The base stations then delay 253 by each of their calculatedreply delay times, while listening for (or attempting to receive)another base station's reply on the hailing channel during that delay.At 254, a first base station's reply delay expires without detectinganother base station's reply, and therefore the first base stationtransmits a reply message. In a first embodiment, the reply messagemerely identifies the base station. In a second embodiment, the replymessage may include system information such as an SSB message, and mayoptionally be followed by an SIB1 message, all optionally transmitted onthe same hailing frequency or an associated frequency band. In a thirdembodiment, the reply message may be a frequency redirect to that basestation's entry channel such as its PBCH broadcast channel, on which theuser device may receive the system information. In a fourth embodiment,the reply message may include a temporary identification that allows theuser device (such as a reduced-capability device) to continuetransmitting short messages at-will on the hailing frequency.

At 255, the other base stations detect the first base station's reply,and therefore they remain silent, or at least avoid replying to thehailing message, in this example. The user device then transmits anintroductory message to the selected base station, the type of replymessage depending on the type of communication that the user deviceseeks to have with the responding entity. At 256, 257, and 258, threealternative outcomes are shown. At 256, the user device receives thereply message which is an SSB message, navigates to the downlink sharedchannel, and receives the SIB1 message, and then transmits a preamblerequesting access on the random access channel. Alternatively, at 257the user device may receive both the SSB and SIB1 messages on thehailing channel, and may then transmit the access preamble on the randomaccess channel. As a further alternative, at 258, the user device mayreceive an identification code and other information enabling the userdevice to continue communicating with the base station on the hailingchannel, or other allocated frequency, using low-complexity procedures.

An advantage of providing a hailing channel on a particular frequencyfor user devices to initiate contact at-will, may be that the separatechannel may avoid interfering with established users on the scheduledchannels. Another advantage may be that the low-complexity hailingprotocols may reduce the computational demands for reduced-capabilitydevices. An advantage of the base stations replying on the same hailingchannel may be that the user device is already on that frequency andtherefore may be ready to detect a reply when it occurs. An advantage ofother prospective user devices listening on the hailing channel beforetransmitting, and withholding their hailing messages if they detectanother device's hailing message, may be that collisions may be avoided.An advantage of the base stations replying to a hailing message after areply delay which is inversely related to the received amplitude, may bethat the user device may connect with the closest base station (or theone with the best reception). Another advantage may be that the userdevice may register on the selected base station without wasting time ona frequency raster blind search and other steps for initial access. Anadvantage of the base stations listening on the hailing channel duringtheir delay times, and refraining from replying if another base stationreplies first, may be to avoid collisions and redundant replies. Anadvantage of using a standard universal frequency for the hailingchannel may be that prospective user devices may readily locate basestations and select among them for the best reception. Another advantagemay be that base stations may monitor just a single frequency to detectprospective new users, thereby reducing demands on the base stations. Anadvantage of the prospective user transmitting a hailing message tomultiple base stations may be that the user device may thereby solicitreplies from multiple base stations at one time.

FIG. 3A is a sequence chart showing another exemplary embodiment of aprocess for a user device to make initial contact with a network,according to some embodiments. Horizontal lines indicate messages of theuser device on a hailing channel, base station 1 on its PBCH, and basestations 1, 2, and 3 on the hailing channel. As depicted in thisnon-limiting example, the user device transmits a hailing message 300 ona hailing channel and then monitors the same hailing channel for aresponse from base stations nearby. The hailing message 300 is receivedby the three base stations, each base station having a differentas-received amplitude because they are at different distances. In thisexample, base station 1 is the closest and base station 3 is farthestfrom the user device. Accordingly, the received amplitudes (suggested bythe sizes of the stippled boxes 304) range from a high amplitude forbase station 1 to a low amplitude for base station 3. The base stationsare configured to delay before replying, the delay being longer for alow-amplitude reception and shorter for a high-amplitude reception, sothat the user device can determine, from the first reply, which basestation is closest. In this example, the delays 301, 302, and 303 ofbase stations 1, 2, and 3 are inversely related to the amplitudes of theas-received signals 304. After each delay, the base stations listen onthe hailing channel to avoid colliding with an ongoing message (LBTintervals shown 305, 306, 307) and then they transmit their replies 311,312, and 313. In this example, all of the base stations that receive thehailing message 300 transmit a reply message 311, 312, and 313. In thisexample, each reply message 311, 312, 313 is a redirect (that is, amessage specifying a different frequency that the recipient may switchto). Each reply message includes a frequency redirect pointer to thebroadcast channel of the replying base station. For example, the replymessage 311 of base station 1 instructs the user device to switch to thebroadcast channel of base station 1, and likewise for messages 312 and313. (For clarity, the broadcast channels of base stations 2 and 3 arenot depicted). The user device then follows the redirect to thebroadcast channel of base station 1 since it was the first replying basestation. The user device then receives a periodically-transmitted SSBmessage 314 on that broadcast channel. The user device then continuesthe registration process from that point. The user device has therebyselected the closest base station (or the one with the best signal), andhas found the first system information message, all without performing ablind search.

A collision between base station reply messages on the hailing channelis still possible, despite the LBT intervals, because two base stationsmay have the same received amplitude and the same calculated delay. Ifthe first two base station messages are transmitted at the same time andcollide, the user device would receive a garbled redirect and maycontinue listening for a better response. If the third reply messagefollows closely after the first two responses, the user device mayconclude that the third base station is only slightly farther away thanthe first two, and therefore may proceed to join the non-colliding basestation. However, if the third reply is substantially later, such astwice as delayed as the first two, then the user device may reject themall and try again by sending another hailing message (after a sufficientdelay to ensure that all base station replies had finished). The firsttwo base stations may then receive the second hailing message, and mayconclude from it that their first replies had likely collided. To avoida second collision, they may add or subtract a random small delay totheir amplitude-dependent delay values, so that their second replymessages likely would not collide a second time, especially if they bothuse LBT intervals to detect a preceding transmission. The user devicemay then receive replies to its second hailing message, select whicheverreply signal arrives first without collision, follow the redirect inthat reply message, receive an SSB message on the selected basestation's broadcast channel, and continue joining that base station.

If a second user device also wishes to find and communicate with asuitable base station, the second user device may detect the first userdevice's hailing message 300, and therefore may withhold its own hailingmessage to avoid interfering with the first user device's process.However, the second user device may also receive the various replymessages 311, 312, 313 and may compare the amplitudes, or other measureof signal quality, of each as-received reply messages 311, 312, 313.Then the second user device may select whichever base stationtransmitted the reply message that was received, by the second userdevice, with the best amplitude. If the second user device prefers thefirst reply message, then the second user device may wait until thefirst user device has completed its communications with the first basestation, to avoid colliding with the first base station's messages.However, if one of the other reply messages (the third one, for example)has the highest amplitude as-received by the second user device, thenthe second user device may immediately follow that redirect andcommunicate with the third base station. In that case, the second userdevice need not worry that its messages would collide with the firstuser device, since it is unlikely that the first user device wouldchoose the third reply message over the first one. This version of theprocedure may depend on (a) multiple base stations replying to thehailing message instead of withholding their replies, and (b) on eachreply message being a redirect so that the subsequent communications donot clog the hailing channel.

FIG. 3B is a flowchart showing another exemplary embodiment of a processfor a user device to make initial contact with a network, according tosome embodiments. As depicted in this non-limiting example, at 351, theuser device transmits a hailing message on a hailing channel at aparticular hailing frequency, which has been allocated for that purpose.Base stations are configured to monitor that frequency to assist newentrants into their network. At 352, multiple base stations detect thehailing message, and measure the received amplitude (or other measure ofsignal quality), and at 353 they calculate delay values inverselyrelated to the received amplitudes. Each base station delays by thatcalculated amount, then checks for traffic during an LBT interval toavoid collisions, and then transmits its reply on the same hailingchannel. (However, if the base station monitors the hailing channelcontinuously during its delay interval, then a separate LBT interval maynot be required.) At 354, the base station with the largest receivedamplitude, and hence the shortest delay, transmits its reply message onthe hailing channel. The reply message is a frequency redirect towardthat base station's broadcast channel, which carries the SSBperiodically. At 355, the user device receives the redirect message,switches to the broadcast channel, and receives the SSB message. Theuser device may ignore the other response messages. In anotherembodiment, the user device may store the other redirects, to use incase there is a problem with the first one. At 356 the user devicecontinues to register with the first base station by receiving the SIMmessage and transmitting a preamble on the random access channel.

An advantage of the base stations replying on the same frequency as thehailing message may be simplicity, since the user device may receive thereplies without changing frequency. Another advantage may be that thebase stations may detect the hailing message, the reply messages ofother base stations, and any additional hailing messages that may betransmitted during the reply period, on that same frequency. Anotheradvantage may be that the user device may select a suitable base stationwithout performing a blind search through multiple frequencies. Anadvantage of the base stations listening on the hailing channel beforetransmitting their reply messages may be to avoid colliding with anongoing response from another base station. An advantage of the basestations using their reply messages to redirect the user device to theirrespective broadcast channels may be to keep the hailing channel freefor future hailing messages, rather than occupying the hailing channelwith the bulky system information messages. Another advantage may be tominimize redundant transmissions by sending the user device to the basestation's regular PBCH in which the SSB is periodically transmitted,instead of providing a special unicast copy for that user device. Anadvantage of the user device storing the various unused reply messagesmay be to follow an alternative redirect in case the first one leads toan unsuitable base station. For example, if the earliest reply messageredirects to a base station that is closed or incompatible with the userdevice's limitations or other requirements, then the user device canfollow the second redirect message and attempt to join the second basestation's network.

FIG. 4A is a sequence chart showing an exemplary embodiment of alow-complexity procedure for base stations to select a prospective userdevice based on the user device's location, according to someembodiments. Horizontal lines show messages of the user device on thehailing channel, messages of a base station on the hailing channel, andmessages of the user device on a random access channel. As depicted inthis non-limiting example, the user device transmits a hailing message401 that indicates the location of the hailing user device. For example,the user device may determine its coordinates (such as its latitude andlongitude) using a map or navigation satellites or other means, and mayinclude that data in the hailing message. At 402, a plurality of basestations (only one shown for clarity) have received the hailing message401, and each base station independently calculates 402 its distancefrom the user device. In addition, each base station also knows wherethe other nearby base stations are located, and each base stationcalculates the distances of all the local base stations from the userdevice. Thus each base station calculates the distance from the userdevice to each base station in the proximity. Each base station thendetermines which base station is closest to the user device's location,and the closest base station then responds to the hailing message. Theother base stations conclude that they are not closest, and they declineto respond. Thus the base stations all perform the same calculationsusing the same set of locations, and hence they all come to the sameconclusion, specifically that a particular base station is closest.Communication between the base stations, although possible, may not beneeded as long as they know the locations of the other base stations.

The closest base station transmits a reply message 403, which in thiscase is an SSB message. Optionally, the reply may also include an SIB1message 404, thereby providing the user device with the informationneeded for communicating with the base station. The user device thentransmits an introductory message (in this case a random accesspreamble) to the replying base station. Accordingly, the user device isshown transmitting a preamble 405 on the random access channel,initiating registration without having to perform a blind search or waitfor a periodic SSB message or search for the SIB1 message.Alternatively, as in the previous example, the base station's replymessage may be a redirect message, causing the user device to switch tothe broadcast channel and receive the SSB there.

As a further alternative, the closest base station may respond with atemporary identification code for the user device to use on the hailingchannel, or other allocated low-complexity channel. Then the user devicemay transmit an introductory message to the base station, and maycontinue to communicate with the base station, on the hailing channel(or other low-complexity channel) according to low-complexity protocols.If the user device then wishes to upgrade its status by joining theregular managed and scheduled channels, the user device may transmit alow-complexity message to the base station on the hailing channel,inquiring the broadcast frequency and optionally the timing of the nextSSB transmission. The user device can then switch to the broadcastfrequency, receive the SSB, and proceed to register on the managedchannels.

In some cases, the closest base station may fail to respond to thehailing message, due to maintenance or lightning or other mishap. Theother base stations, having calculated that they are not the closest oneto the user, may decline to reply, as mentioned. However, the other basestations may continue to monitor the hailing channel, and thereby failto detect the expected reply message of the closest one. When theclosest one fails to reply within a predetermined time, the other basestations may determine that the closest one is unexpectedly indisposed,and therefore the second-closest base station may then transmit a replymessage instead.

FIG. 4B is a flowchart showing an exemplary embodiment of alow-complexity procedure for a user device to obtain network systeminformation, according to some embodiments. As depicted in thisnon-limiting example, at 451, a prospective user device transmits ahailing message on a hailing channel allocated for randomly timedmessages and monitored by multiple base stations. The hailing messageincludes an indication of the prospective user device's location, suchas latitude and longitude, a street address, map coordinates, or otherlocation indicator recognizable to the base stations. At 452, a numberof base stations in range have detected the hailing message andretrieved the user device's location information. Each base stationalready knows its own location, as well as the locations of the otherbase stations in the region. At 453, each base station calculates thedistance from the prospective user device to its own location. At 454,each base station also calculates the distance from the user device toeach of the other base stations. At 455, each base station determineswhich of the base stations is closest to the prospective user device. Inthis example, the base stations also know which other base stations areunavailable to accept new entrants, and may exclude those base stationsfrom the calculations. The base stations may exchange updates as totheir availability periodically, or whenever one of them changesavailability, so that the other base stations will know which ones areavailable. Since the base stations then have the same data regardinglocations and availability, they all reach the same conclusion as towhich available base station is closest. At 456, the closest oneresponds to the hailing message by transmitting a reply message. Thereply message in the depicted case is either an SSB message thatprovides sufficient system information to enable the prospective userdevice to find and receive downlink messages, or a frequency redirectindicating the base station's PBCH frequency. Alternatively, the replymessage may include low-complexity entry information, such as atemporary identifier, for low-complexity messaging on the hailingchannel. At 457, the user device proceeds to communicate with the basestation as directed.

An advantage of a prospective user device transmitting a hailing messagethat includes the user device's location, may be that it enables thebase stations to self-select the closest one for replying to the userdevice. An advantage of networks providing a hailing channel, on whichmultiple base stations in a region can detect hailing messages and replyto them, may be that the prospective user device may broadcast to all ofthe base stations in range by transmitting a single hailing message.Another advantage may be that the hailing message and the reply message,being on an allocated frequency separate from the scheduled messagefrequencies, may avoid interfering with the scheduled channels. Anadvantage of the base stations calculating the distances from the userdevice location to themselves, and also the distance to other proximatebase stations, may be that each base station can thereby determine whichof the base stations is closest, and therefore which base station is torespond. An advantage of determining which base station is closest tothe prospective user device may be that the closest one may provide thebest reception. An advantage of the various base stations having thesame data regarding the locations of the various base stations, may bethat their distance calculations may be consistent with each other. Anadvantage of the base station calculations all being consistent witheach other may be that the base stations all reach the same conclusionas to which available base station is closest and should reply. Anadvantage of the base station replying with an SSB message may be thatthe reply thereby provides essential system information, on demand, tothe prospective user device. Another advantage may be that theprospective user device may avoid doing a blind search. An advantage ofproviding an SIB1 message concatenated with the SSB message may be thatit provides sufficient system information for the prospective userdevice to transmit messages to the network, without waiting for aperiodic SIB1 transmission on the PDSCH. An advantage of the prospectiveuser device transmitting a preamble message on the random access channelmay be that this initiates the registration process on the regularchannels while freeing up the hailing channel for other entrants. Anadvantage of the closest base station responding to the hailing messagewith a redirect message to its PBCH may be that the hailing frequencymay be kept free for other hailing messages. An advantage of the basestation including a low-complexity identification to the user device inthe reply message may be that the user device may begin communicatingwith the base station upon receipt, instead of carrying out a series ofcomplex requirements to join the scheduled channels.

FIG. 5A is a sequence chart showing an exemplary embodiment of alow-complexity procedure for base stations to cooperate in decidingwhich base station will respond to a hailing message, according to someembodiments. The horizontal lines indicate preparation steps of aprospective user device, its messages on a hailing frequency, messagesof base station 1 on the hailing frequency, and actions of base stations2 and 3. As depicted in this non-limiting example, a prospective userdevice determines its location 501 using satellite signals or a map oran address for example, and then determines a local hailing frequencyaccording to the location. The prospective user device then transmits ahailing message 502 on the hailing frequency. The hailing message isreceived by multiple base stations (three shown) and each base stationmeasures the amplitude of the received signal. The base stations (ortheir respective core networks, not shown) then communicate 503 witheach other over a backhaul link (such as a cable). The negotiation (504,in dash) may include the base stations comparing their receivedamplitudes and other relevant data, and then determining which basestation is to respond to the hailing message. For example, the basestations may select the base station that has the best received signal,which in this case is base station 1. Then, after a listen-before-talkinterval 505, base station 1 replies with a welcome message 506 on thehailing frequency. In the welcome message 506, the chosen base stationidentifies itself and provides SSB and SIB1 system information files aswell as user-specific information such as a C-RNTI identification forthe user device, plus a timing adjustment and/or frequency adjustmentand/or a power adjustment, configured to bring the user device'smessages into compliance with the base station's resource grid. Thewelcome message 506 may also provide an indication of a frame boundaryrelative to the welcome message 506 for example, to further align theuser device's timing. Alternatively, the welcome message 506 may providea frequency redirect to the broadcast channel or other entry channel.The user device then replies with an acknowledgement 507 on the hailingfrequency, after applying the frequency and timing adjustments. Afterregistering with base station 1, the user device may then communicateusing the regular 5G channels (PUSCH etc.) according to the systeminformation provided.

In another embodiment, the user device may request that thecommunications continue on the hailing frequency instead of joining thescheduled channels. For example, if the user device is a very light user(that is, it has only short and infrequent messages) and if the basestation supports brief general messaging on the hailing channel, thebase station may concur. Using the hailing channel for brief andinfrequent messaging may keep the scheduled channels clear forhigher-priority users. Alternatively, the base station may redirect theuser device to a random access channel or other channel allocated forlight users, instead of camping on the hailing frequency. The networkdatabase and/or the base station may specify limitations or requirementsfor access to such a low-complexity channel, for example by specifyinglimits on message size, transmissions per day, QoS limits, or otherpredetermined limits.

As another alternative, the user device may be a temporary pass-throughvehicle which seeks to transmit a single email or receive a single filewhile briefly in range. In that case, the transient user may, forsimplicity, request to remain on the hailing frequency for the brieftime.

As a further alternative, the user device may be a long-term resident ofthe network but with light communication needs, and therefore may wishto set up the base station connection for future use, even if the userhas no messages to send at this time.

In some embodiments, the base stations may determine which base stationis to respond, based in part on how much traffic each base station iscarrying. For example, each base station may indicate how much trafficit is carrying or what fraction of its maximum traffic capacity isfilled. Then the base stations (or a higher-level manager) may select alightly-loaded base station that is farther from the user device,instead of a closer one that is currently heavily loaded. Sending newusers to base stations that are carrying less traffic than others, iscalled “load-leveling”.

As a further alternative, the user device may specify in its hailingmessage that it needs a low-complexity channel instead of the complexmanaged channels of regular 5G or 6G. Then the base stations, during thenegotiation process, may determine which of the base stations canaccommodate low-complexity communications, and therefore may select oneof those base stations to reply. On the other hand, the user device mayindicate, using flags for example, that it needs both low latency andhigh reliability, or that the message is an emergency call, or otherspecial request. Those requirements may affect the base stations'decision as to where to send the new user, and what type of replymessage would be appropriate to accommodate the needs.

In some embodiments, an administrator or other authority may decidewhich base station is to reply. Each of the base stations may conveytheir information, such as the received amplitude and current trafficconditions, to the administrator, and the administrator may then selectone of the base stations to serve the user device, at least initially.

FIG. 5B is a flowchart showing an exemplary embodiment of alow-complexity procedure for a user device to communicate with anassigned base station, according to some embodiments. As depicted inthis non-limiting example, at 551, the prospective user devicedetermines a local hailing frequency from an on-line database, or apreviously established convention, or information built-in or providedon a plug-in card, or otherwise. At 552, the user device transmits ahailing message on the hailing frequency, the hailing message indicatingthat the user device seeks contact with an available base station. At553, the hailing message is received by multiple base stations, each ofwhich measures its received signal amplitude. At 554, the base stations(or their connected core networks) compare the amplitude results of thevarious base stations by communication through a backhaul network, suchas a wired or optical cable or other connection, or a wirelessconnection not interfering with the hailing frequency. The base stationsmay also indicate to each other how much traffic they are carrying, orhow much unused capacity they have, or other measure of theiravailability to accommodate the new user. In addition, if the new userindicates, in its hailing message, that it needs special accommodationsuch as a low-complexity channel, or a legacy channel, or an especiallyhigh QoS or other performance, or other request, the base stations canconsider that information in their mutual decision on which base stationwill respond. In a first embodiment, the base stations may determinewhich base station will reply to the hailing message by mutual agreementamong the receiving base stations in cooperation. In a secondembodiment, the determination may be made by a supervisor entity (notshown) such as a core network shared by the base stations, or otheradministrative entity configured to manage the individual base stationsand to decide how to allocate new users among the base stations. At 555,the assigned base station transmits a welcome message, on the samehailing frequency in this example, thereby providing a redirect to thebroadcast channel, or other data that the prospective user device needsto complete the registration. That data may include synchronizationinformation regarding the network time-base including frame boundariesand the like, along with adjustment recommendations regarding the userdevice's frequency scale, timing, power level, and the like. Forexample, the base station may recommend time adjustments relative to thewelcome message, to align the new user with slot boundaries.Alternatively, the timing adjustments may be relative to the user'shailing message instead of the welcome message, and hence may accountfor the two-way travel time of the signal. The base station may alsoprovide a code identifying the network that the user device is joining,along with a temporary identification such as a C-RNTI for the userdevice, among other user-specific information. At 556, the user deviceadjusts its time, power, and frequency as suggested, and transmits anacknowledgement on the hailing frequency, or on one of the regularchannels such as the random access channel or the uplink control channelof the base station, using its newly-assigned C-RNTI identificationcode, thereby completing the registration. Optionally, in dash, at 557the user device and the base station may exchange further informationregarding the capabilities and limitations and QoS requirements of theuser device. Optionally, at 558, if the user device is a light user withonly short and seldom messages, the user device may continue tocommunicate on the hailing frequency if permitted by the base station,or on another channel allocated by the base station for light users orthose requiring low-complexity procedures.

An advantage of the base stations communicating with each other onbackhaul may be that they can cooperatively determine which base stationshould reply to the hailing message. Another advantage may be that thedecision as to which base station will respond, may be based on theamplitudes of the received signals at the various base stations, or onthe calculated distances of the user device from the base stations, oron other criteria related to signal quality. Another advantage of thebase station negotiations may be load-leveling, wherein the basestations may mutually decide (or an administrator may decide) to connectthe user device with a particular base station that has low trafficinstead of a closer base station which is under a heavy load. Anadvantage of the base stations communicating with each other (or with anadministrator) may be that a suitable base station for the user devicemay be determined without the user device having to do a time-intensiveblind search. An advantage of the assigned base station transmitting awelcome message on the same frequency as the hailing message, may bethat the user device is already connected to the hailing channel andtherefore may receive the welcome message readily without switchingfrequencies. Alternatively, a second frequency may be provided for thereply messages. An advantage of providing a separate channel for thereply messages may be to keep the hailing channel relatively free forother new entrants.

The systems and methods further include using artificial intelligence(AI) or machine learning (ML) in allocating traffic to various availablebase stations. As the number of base stations increases in urban areasand automated manufacturing sites, selection of which base station is toaccept a new user is often a complex problem, with proximity, signalclarity, traffic level, capacity of each candidate base station, the newuser's service requirements and expected messaging volume, and manyother factors influencing the assignment decision. In such problems,artificial intelligence or machine learning may provide improvedmanagement and reduced computational expense. For example, AI canprovide optimal, or at least improved, decision-making that accounts forall of the factors listed above and others, while optimizing or at leastenhancing an overall network performance metric.

Typically an AI structure (such as a neural net) includes a large numberof adjustable internal variables in functions configured to relate aplurality of input parameters to an output decision or prediction. Theinput parameters may include the distances from the user device to eachof the available base stations, the traffic loads at each, and the otherfactors listed above, among other factors. Using a supercomputer,usually, the variables are iteratively adjusted until the AI structurereliably provides a desired output, such as accurate predictionsregarding network performance according to the user allocation decision,or other solutions that result in an improvement of the performancemetric. Alternatively, the output of the AI structure may include anindication of which base station should respond to the hailing message.In many multi-variable problems, an AI structure may be able to providebetter solutions than a human expert, and in less time, especially inrapidly changing conditions in high-density wireless environments. Byapplying such an AI structure to the base station selection problem, and“training”, or iteratively adjusting, the variables according to a largenumber of observed network situations and operational decisions, the AImodel may reach an acceptable level of accuracy, and hence the algorithmmay help base stations to make better decisions regarding the allocationof their resources, including accepting newly arriving user devices, andmay do so faster or more accurately than a human expert could. Inaddition, the same or similar AI structure may enable improveddecision-making for distributing the existing users among the availablebase stations, such as shifting users from one cell to another forload-leveling or to make room for a high-priority demand from aparticular user, or other circumstance. As a result, network performancemay be improved, the new user device may be served with better receptionby an available base station, the other base stations may be shieldedfrom overloading, and the overall user satisfaction may be improved.

Due to the potentially large number of inputs and adjustable variablesin the model, and the very large amount of training data likely neededfor convergence of the model, the AI structure is preferably prepared ina supercomputer. The supercomputer may be a classicalsemiconductor-based computer, with sufficient speed and thread count andprocessor count to perform the model training in a feasible amount oftime. Alternatively, the supercomputer may be a quantum computer having“qbits” or quantum bits as its working elements. Quantum computers mayprovide special advantages to solving AI models because they can veryrapidly explore a complex terrain of values, such as the highlyinterrelated effects of the various inputs on the output results.Therefore, the systems and methods include a quantum computer programmedto include an AI structure and trained on network data in which new orexisting users may be allocated to the various base stations, and thesubsequent network performance is then measured. By adjusting thevariables in the AI model to accurately predict the network performancewhen the user allocation rules are changed, the AI model can then assistnetwork administrators in placing new users with each of the basestations, and may also guide handoff decisions for load-levelling orimproved reception, among many other compromises involved. Forconvenience, an algorithm may be derived from the AI model, either as asimplified version of the AI structure, or a different calculation toolsuch as a subroutine or a tabulation of values. The base stations ortheir core networks may then use the algorithm to allocate users amongparticipating base stations to optimize network operations and providebetter user satisfaction overall.

The systems and methods disclosed herein further include exemplaryformats of messages associated with hailing and registration processes,according to some embodiments.

FIG. 6A is a schematic showing an exemplary embodiment of alow-complexity hailing message, according to some embodiments. Asdepicted in this non-limiting example, the hailing message 601 includesan optional demodulation reference 602 which may be short, a type-code603 indicating that the message is a hailing message, and optionally aset of flags 604 such as some number of bits indicating something aboutthe hailing device, such as indicating whether the hailing user alreadyhas the system information associated with the base station. In thatcase, the new user device may be ready to transmit a random accesspreamble as soon as a suitable base station is selected. Alternatively,the flags 604 may indicate that the communication is an emergency calland that the user therefore demands accelerated registration on the basestation's cell. The flags 604 may include a “seek-code” which is a codeindicating what type of entity the hailing user is seeking. As anon-limiting specific example, two bits of the flags 604 may be set tobinary “00” if the hailing user wishes to connect with a base station(V2N), or “10” to seek another vehicle V2V), or “11” to seek anywireless entity (V2X), and the code “01” may be reserved for some futureuse. The flags 604 may also indicate that the user device is areduced-capability device or requests a legacy protocol. The flags mayalternatively indicate that the user device requests high QoS, orextremely low latency, or extremely high reliability communications,among other options. As mentioned, the example is non-limiting; artisansmay devise other hailing messages with other fields and other sizes,without departing from the appended claims.

An advantage of providing a leading demodulation reference 602 may bethat it enables the base stations to better interpret the rest of themessage. The demodulation reference may be, for example, just tworesource elements exhibiting the maximum and minimum amplitude levels,and the maximum and minimum phase levels of the modulation scheme,thereby enabling the base stations to calculate the intermediate levelsby interpolation. The base station can then demodulate the subsequentmessage elements according to the amplitude and phase levels sodetermined. An advantage of providing the type-code 603, indicating thatthe message 601 is of type hailing, may be to implicitly request aresponse from any base station in range. An advantage of the optionalflags 604 may be to indicate whether the hailing node is areduced-capability device, or whether the hailing message is anemergency call, among other options. Another advantage may be that thehailing message 601 may be short. For example, the message 601 includingjust the message-type field 603 may be represented in six to ten bits,which can be transmitted in three to five QPSK message elements.Alternatively, if the demodulation reference 602 and flags 604 areincluded, six to twelve message elements may be sufficient, althoughmany other formats are possible. An advantage of including a seek-codein the hailing message may be that wireless entities other than thosebeing sought may disregard the message, while entities of the type beingsought may reply.

The examples refer to a standard modulation scheme of separate amplitudeand phase modulation multiplexed in each message element. Alternatively,the message may be modulated according to PAM or pulse-amplitudemodulation, in which two signals are separately amplitude modulated andthen combined with a 90-degree phase difference. For the purposes of thepresent disclosure, those and other modulation schemes involvingamplitude and/or phase modulation are equivalent. It is immaterial whichtype of modulation scheme is employed, as long as the receiving entityknows how to demodulate and interpret the message.

FIG. 6B is a schematic showing an exemplary embodiment of alow-complexity hailing message with identification, according to someembodiments. As depicted in this non-limiting example, a hailing messagewith ID 611 may include a type-code 615 indicating that the message is ahailing message with ID (identification), followed by the identificationcode 616 of the transmitting user device. The identification code 616may be a self-selected or random code such as an 8-bit code, or it maybe the user device's MAC address or a portion thereof, or other codesuitable for identifying the hailing node in further messages. Theidentification code 616 may identify the transmitting user device sothat the base stations may subsequently transmit messages specificallyaddressed (that is, unicast) to the hailing user device. Optionally, themessage 611 may further include a demodulation reference 612, andoptionally a space or gap 613 of zero transmission (or unmodulatedcarrier, or other signal not resembling the data) between thedemodulation reference 612 and the type-code 615. The gap 613 may assistthe receiving base stations in separating the demodulation reference 612from the rest of the message, and may also give the base stations timeto process the demodulation reference 612 and adjust the modulationcalibration levels before receiving the remaining message elements.

For V2X applications, the example of FIG. 6B may be especiallyadvantageous because it includes the ID code of the transmittingvehicle, so that the replying wireless entities can transmit theirreplies unicast to the hailing vehicle, thereby initiating communicationbetween the hailing vehicle and the other wireless entity. In addition,the type-code 615 may include an indication of which entities are beingsought by the message, such as one type-code for hailing messagesseeking a network access, a second code seeking only a vehicle, and athird code seeking any entities within range, among many other possibletypes of recipients.

FIG. 6C is a schematic showing an exemplary embodiment of alow-complexity hailing message with location data, according to someembodiments. As depicted in this non-limiting example, the hailinglocation message 621 includes a type-code 623 indicating the message isa hailing message with location data, a seek-code 624 indicating thekinds of entities being sought by the hailing entity, followed by thelocation coordinates of the hailing user device, such as the latitudeand longitude 625 as shown, an optional identification code 626, and anoptional CRC or parity or other error check code “PAR” 627. Theidentification code 626 may be a self-selected or random code such as an8-bit code, or it may be the user device's MAC address or a portionthereof, or other code suitable for identifying the hailing node infurther messages.

The coordinates 625 may be encoded for compactness. For example, eachcoordinate may be presented in degree fractions, that is, in degrees butwith the whole-degree portion suppressed, so that only the fractionalportion (to the right of the decimal point) is included in the message.It may not be necessary to specify the whole-degree portion because therange of the user-transmitted hailing message is unlikely to extend afull degree of latitude or longitude, which is about 100 km in most ofthe world. By specifying the fractional portion of each coordinate, each14-bit value may provide a resolution of about 6 meters, which isgenerally comparable to GPS resolution. In other embodiments, thecommunicating entities are interested in recipients within a range ofonly a few hundred meters, such as vehicles in traffic. In that case,the coordinates 625 may be formatted as degrees, minutes, and seconds,but with only the seconds and fractional seconds included in the message(that is, whole degrees and minutes suppressed). Meter-scale resolutionmay be obtained with 10 or 11 bits. As mentioned, the example isnon-limiting; artisans may devise other hailing messages with otherfields and other sizes, without departing from the appended claims.

An advantage of including the user's location in a hailing message maybe that the receiving base stations may thereby determine which basestation is closest to the user device. An advantage of providing atype-code may be to inform the receiving entity that the messageincludes the user device's location or identification code or both.Another advantage may be that the hailing message is short. An advantageof providing the user device's self-selected identification code may beto enable the responding base station to transmit unicast to the userdevice, particularly to transmit its C-RNTI upon registration.

FIG. 7A is a schematic showing an exemplary embodiment of alow-complexity hailing reply message with redirect, according to someembodiments. As depicted in this non-limiting example, the hailing replyredirect message 701 is transmitted by a base station in response to ahailing message, directing the user device to switch to a differentfrequency for further communication. The hailing reply redirect message701, in this example, includes a type-code 703 indicating the message isa hailing reply with redirect, a sign bit 704 and a 7-bit frequencydifference 705 indicating the base station's broadcast or random accesschannel relative to the hailing frequency. The frequency difference isgiven, in this example, as a multiple of 15 kHz. Hence the frequencyredirect with 8 bits including sign may span 3840 kHz. In anotherembodiment, the frequency difference 705 may have 16 bits includingsign, providing nearly 1 GHz span at 15 kHz resolution. Other encodingsare possible for different ranges and different frequency resolution.For greater flexibility, the frequency may be specified as an absolutefrequency instead of a frequency offset relative to the hailingfrequency. If the frequency is specified as an offset, it may be offsetfrom a standard value, such as 2 GHz, instead of the hailing or replyfrequencies. As mentioned, the example is non-limiting; artisans maydevise other hailing messages with other fields and other sizes, withoutdeparting from the appended claims.

As an option, the type-code 703 may be configured to act as a shortdemodulation reference as well as an indication that the message is ahailing response. For example, the first message element in thetype-code 703 may modulated according to the maximum amplitude andmaximum phase of the modulation scheme, and the second message elementmay be modulated according to the minimum amplitude and phase, followedby one or more message elements specifically indicating that the messageis type hailing response. The user device can then recalibrate itsdemodulator levels according to the first and second message elementsacting as demodulation reference elements, and thereby demodulate theremaining message more accurately.

An advantage of the hailing response redirect message may be that it mayprovide a frequency redirect to assist the user device, by pointing toanother frequency, which may enable the hailing user device to proceedwith a registration procedure. Another advantage may be that byredirecting the user device to another channel, the replying basestation may thereby keep the hailing channel free for subsequent hailingmessages. Another advantage may be saving time, since the user devicemay then carry out an access procedure without having to do a blindsearch. Another advantage may be that the message is short, in thedepicted example.

FIG. 7B is a schematic showing an exemplary embodiment of alow-complexity hailing reply redirect message to the random accesschannel, according to some embodiments. As depicted in this non-limitingexample, the reply message 711 is a base station's reply to a userdevice's hailing message. The depicted reply message 711 includes atype-code 715 indicating the type of message, and a frequency field 716indicating the frequency of another channel, which in this case is therandom access channel (or alternatively the broadcast channel or someother channel) of the base station, plus optionally an error code 717such as a parity check or hash code of the message. The user device canthen switch to the random access channel and either submit a preamble,if the user device already has the system information and is ready tojoin the network, or a low-complexity entry message requesting furtherlow-complexity communications on the random access channel or otherchannel that the base station may indicate for such communications.

FIG. 7C is a schematic showing another exemplary embodiment of alow-complexity hailing reply redirect message, this time with twofrequencies indicated, according to some embodiments. As depicted inthis non-limiting example, the hailing reply message 721 includes atype-code 725 indicating that the message provides two frequencyredirects, followed by a redirect to the random access channel 726 and aredirect to the broadcast channel 727 of the responding base station.Optionally, an error-check field 728 may be appended. The dual frequencyredirect option allows the prospective user device to jump to the PBCHto get the SSB if the user does not yet have updated system information,and to jump to the random access frequency directly if the user alreadyhas the system information.

Optionally, the message 721 may include a leading demodulation reference724 before the type-code 725, and a following demodulation reference 729after the parity check field 728 (or elsewhere in the message). Thereceiving user device may use the two demodulation references 724-729 tomitigate noise and interference, and thereby enable a more accuratedemodulation of the message 721. For example, the user device canmeasure the amplitude and phase levels of each element of the message721 and store that data in a memory, for example, and then candemodulate the stored data according to the two demodulation references724-729. For example, the user device can average the two demodulationreferences 724-729 to obtain an average value of the amplitude and phaselevels during the message 721. Alternatively, the user device canprepare an interpolated or weighted average of the leading and followingdemodulation references 724-729, weighted according to the distance ofeach message element from each of the demodulation references 724-729.For example, the first element of the type-code 725 may be demodulatedaccording to modulation levels derived by weighting the leadingdemodulation reference 724 much more heavily than the followingdemodulation reference 729, due to proximity of that message element tothe leading demodulation reference 724. A centrally-positioned elementof the message 721, such as the first message element of the secondfrequency field 727, may be demodulated according to modulation levelswith equal weighting of the leading and following demodulationreferences 724-729. Likewise, the final message element of the paritycheck field 728 may be demodulated primarily by the followingdemodulation reference 729 because that demodulation reference is muchcloser than the leading demodulation reference 724. In this way, noiseand interference that varies in time (or frequency) between thebeginning and ending of the message 721 may be compensated moreaccurately than by uniformly averaging the two demodulation references,724-729, and much more accurately than using a single demodulationreference for the entire message 721, according to some embodiments.

An advantage of providing a type-code may be to indicate the type ofmessage so that the receiving user device can interpret each fieldproperly. An advantage of providing a frequency redirect may be toindicate a frequency of another channel at which the user device canproceed with registration. An advantage of providing two frequencyredirects may be to allow the user device to choose whether to acquirethe system information messages SSB and SIB1, or to proceed directly tothe random access channel, among many other options for the redirectdestinations. An advantage of providing two demodulation references atopposite ends of the message (or elsewhere in the message) may be toenable a more accurate demodulation of the message element despitevariable noise and interference.

5G has enormous potential for high-end user devices such as computersand mobile phones with advanced software and powerful processors.However, many future communication applications are expected to involvea completely different family of devices, with substantially lower cost,lower performance, and lower service demands than past wireless systems.It would be inefficient to establish a separate wireless technologyadapted to low-end devices, but overlapping and competing with 5G/6G,especially since there is only one frequency spectrum which all wirelesstechnologies must inescapably share. Low-demand devices could beupgraded to comply with 5G and future 6G standards at substantial extracost, which would exclude or substantially attenuate many promisingcost-constrained use cases. A much more efficient path forward would beto provide, in 5G and 6G, optional low-complexity procedures and alow-complexity channel or frequency, which can accommodate devices withfar lower performance capabilities than current wireless devices.Low-complexity protocols, configured to enable reduced-capability userdevices, may minimize demands on 5G and 6G base stations, and may beconfigured to avoid interfering with the higher-priority applicationswhich may be communicating concurrently on the scheduled channels. It ispossible to provide such low-complexity protocols and low-complexitychannels without impacting, or at most minimally impacting, thescheduled network because reduced-capability devices generally do notrequire low latency, high reliability, large messages, wide bandwidth,or high usage. On the contrary, most of the emergent IoT applicationsinvolve infrequent, short messages transmitted locally by single-purposesensors or actuators, placing very minimal demands on the network. Byaccessing the low-complexity options, such MTC devices may dedicatetheir attention primarily to serving their intended application, ratherthan spending their time and energy merely fulfilling complex 5G/6Grequirements. Rapid proliferation of wireless applications willnaturally result.

The systems and methods disclosed herein are intended to provide suchnon-interfering low-complexity options. It is important to incorporatethe disclosed options and procedures early, while the 6G standards arestill being developed. Experience with 4G demonstrates that trying toredesign an already fully established wireless technology to accommodatea different family of electronics is difficult. The options describedherein include procedures for user devices to initiate contact with basestations using hailing messages and prototype low-complexity messageformats for each of the above. When low-complexity procedures areincorporated in the 5G and 6G standards, these procedures will openopportunities for many low-demand applications involving low-costwireless devices, applications that would not have been feasible absentthe disclosed low-complexity procedures.

The wireless embodiments of this disclosure may be aptly suited forcloud backup protection, according to some embodiments. Furthermore, thecloud backup can be provided cyber-security, such as blockchain, to lockor protect data, thereby preventing malevolent actors from makingchanges. The cyber-security may thereby avoid changes that, in someapplications, could result in hazards including lethal hazards, such asin applications related to traffic safety, electric grid management, lawenforcement, or national security.

In some embodiments, non-transitory computer-readable media may includeinstructions that, when executed by a computing environment, cause amethod to be performed, the method according to the principles disclosedherein. In some embodiments, the instructions (such as software orfirmware) may be upgradable or updatable, to provide additionalcapabilities and/or to fix errors and/or to remove securityvulnerabilities, among many other reasons for updating software. In someembodiments, the updates may be provided monthly, quarterly, annually,every 2 or 3 or 4 years, or upon other interval, or at the convenienceof the owner, for example. In some embodiments, the updates (especiallyupdates providing added capabilities) may be provided on a fee basis.The intent of the updates may be to cause the updated software toperform better than previously, and to thereby provide additional usersatisfaction.

The systems and methods may be fully implemented in any number ofcomputing devices. Typically, instructions are laid out on computerreadable media, generally non-transitory, and these instructions aresufficient to allow a processor in the computing device to implement themethod of the invention. The computer readable medium may be a harddrive or solid state storage having instructions that, when run, orsooner, are loaded into random access memory. Inputs to the application,e.g., from the plurality of users or from any one user, may be by anynumber of appropriate computer input devices. For example, users mayemploy vehicular controls, as well as a keyboard, mouse, touchscreen,joystick, trackpad, other pointing device, or any other such computerinput device to input data relevant to the calculations. Data may alsobe input by way of one or more sensors on the robot, an inserted memorychip, hard drive, flash drives, flash memory, optical media, magneticmedia, or any other type of file-storing medium. The outputs may bedelivered to a user by way of signals transmitted to robot steering andthrottle controls, a video graphics card or integrated graphics chipsetcoupled to a display that maybe seen by a user. Given this teaching, anynumber of other tangible outputs will also be understood to becontemplated by the invention. For example, outputs may be stored on amemory chip, hard drive, flash drives, flash memory, optical media,magnetic media, or any other type of output. It should also be notedthat the invention may be implemented on any number of different typesof computing devices, e.g., embedded systems and processors, personalcomputers, laptop computers, notebook computers, net book computers,handheld computers, personal digital assistants, mobile phones, smartphones, tablet computers, and also on devices specifically designed forthese purpose. In one implementation, a user of a smart phone orWi-Fi-connected device downloads a copy of the application to theirdevice from a server using a wireless Internet connection. Anappropriate authentication procedure and secure transaction process mayprovide for payment to be made to the seller. The application maydownload over the mobile connection, or over the Wi-Fi or other wirelessnetwork connection. The application may then be run by the user. Such anetworked system may provide a suitable computing environment for animplementation in which a plurality of users provide separate inputs tothe system and method.

It is to be understood that the foregoing description is not adefinition of the invention but is a description of one or morepreferred exemplary embodiments of the invention. The invention is notlimited to the particular embodiments(s) disclosed herein, but rather isdefined solely by the claims below. Furthermore, the statementscontained in the foregoing description relate to particular embodimentsand are not to be construed as limitations on the scope of the inventionor on the definition of terms used in the claims, except where a term orphrase is expressly defined above. Various other embodiments and variouschanges and modifications to the disclosed embodiment(s) will becomeapparent to those skilled in the art. For example, the specificcombination and order of steps is just one possibility, as the presentmethod may include a combination of steps that has fewer, greater, ordifferent steps than that shown here. All such other embodiments,changes, and modifications are intended to come within the scope of theappended claims.

As used in this specification and claims, the terms “for example”,“e.g.”, “for instance”, “such as”, and “like” and the terms“comprising”, “having”, “including”, and their other verb forms, whenused in conjunction with a listing of one or more components or otheritems, are each to be construed as open-ended, meaning that the listingis not to be considered as excluding other additional components oritems. Other terms are to be construed using their broadest reasonablemeaning unless they are used in a context that requires a differentinterpretation.

The invention claimed is:
 1. A base station of a wireless network, thebase station containing non-transitory computer-readable mediacontaining instructions that, when executed by a computing environment,cause a method to be performed, the method comprising; determining apredetermined hailing frequency allocated for user devices to transmithailing messages; receiving a broadcast hailing message from aprospective user device on the predetermined hailing frequency, whereinthe broadcast hailing message indicates that a reply message isrequested from base stations that can accept a new user; determiningthat the base station can accept a new user; measuring an amplitude ofthe broadcast hailing message as received by the base station;calculating a delay time inversely related to the amplitude, the delaytime not exceeding a predetermined maximum delay time; and after thedelay time, transmitting, according to a predetermined transmissionpower level, a reply message to the user device on the predeterminedhailing frequency.
 2. The base station of claim 1, the method furthercomprising: if the base station detects a communication from anotherbase station to the user device during the delay time, waiting apredetermined listen-before-talk (LBT) interval, and then, if no furthertransmissions are detected during the LBT interval, transmitting thereply message to the user device on the predetermined hailing frequency.3. The base station of claim 1, wherein the reply message specifies aparticular frequency, or an offset indicating the particular frequency.4. The base station of claim 3, wherein the particular frequency isrelated to a physical broadcast channel or a random access channel ofthe base station.
 5. The base station of claim 1, wherein the replymessage indicates a first frequency and a second frequency differentfrom the first frequency.
 6. The base station of claim 1, wherein thereply message specifies system information of the base station.
 7. Awireless network comprising a first base station in signal communicationwith a plurality of user devices, the first base station configured to:a) determine a maximum traffic capacity of the first base station; b)determine a predetermined limit less than 1; c) determine a hailingfrequency allocated for user devices to transmit discovery messages tobase stations; d) measure a fraction comprising a current traffic levelof the first base station divided by the maximum traffic capacity of thefirst base station; e) if the fraction is below the predetermined limit,receive a hailing message broadcast by a prospective user device; f)measure a value related to the hailing message; g) communicate the valueand the fraction to a network administrative entity; and h) uponreceiving, from the network administrative entity, an instruction toaccept the prospective user device, transmit a reply message to theprospective user device.
 8. The wireless network of claim 7, wherein thevalue comprises at least one of: a) an amplitude of the as-receivedhailing message; b) a power level of the as-received hailing message; c)a signal quality of the as-received hailing message; and d) asignal-to-noise ratio of the as-received hailing message.
 9. Thewireless network of claim 7, wherein the value comprises a distancebetween the prospective user device and the first base station.
 10. Thewireless network of claim 7, further comprising: a) while the fractionexceeds the predetermined limit, determining whether a hailing message,received on the hailing frequency, is an emergency message; b) if thehailing message is not an emergency message, ignoring the hailingmessage; c) if the hailing message is an emergency message, determiningwhether another base station has responded to the emergency message; andd) if no other base station has responded to the emergency message,transmitting a reply message to the prospective user device.
 11. Thewireless network of claim 7, further comprising: a) if the hailingmessage indicates that the prospective user device has not received anSSB (synchronization signal block) message of the first base station,transmitting, in the reply message, system information of the first basestation.